The present invention relates generally to prosthetic devices, and more particularly to an improved mobile prosthetic device operable for supporting a user in sitting and standing positions.
Persons confined to wheelchairs become uncomfortable and psychologically depressed in prolonged periods of being seated, and situations wherein being seated is inappropriate. It is more comfortable and involves less stress for such users to stand in appropriate situations, and to periodically assume an upright, standing position. In situations where other persons are seated, there is less of a problem. In situations where it is inappropriate to be seated, as in some work environments, business or social circumstances, a user can best perform and feel more comfortable when in a standing position.
Certain prior prosthetic devices provide for sitting and standing positions of users. These have involved such problems as excessive complexity, high manufacturing costs, excessive size and weight, lack of fully effective systems for assuming standing and sitting positions and other shortcomings. The improved prosthetic apparatus according to the invention addresses such problems and shortcomings by providing a prosthetic apparatus for the positioning and support of a user in standing and in seated positions. The apparatus includes a base with front and rear wheels, the front wheels being pivotable, and the rear wheels being separately powered for controlling the direction of rotation and the speed of each of the rear wheels to control forward and rearward movement, and for steering. Lifter means including a piston on the base, a movable member in telescoping relation with the piston, is operable by mechanical drive means to move the movable member relative to the piston. User controlled electrical power means for operating the lifter means urges a movable member upwardly and downwardly. Electrical power means are controllable by the user by moving the movable member and a seat between the user-standing and user-seated positions, and for controlling movement of the apparatus by selective powering of respective rear ground wheels. The support frame mounted on the movable member has a seat at its rear edge portion pivotally mounted on the movable member, and with the front or outer edge portion of the seat being pivotally connected with the base for movement of the seat between its extended user-seated position and its retracted user-standing position.